Other forms: discharged, discharges, discharging
To discharge somebody is to let them go officially. Discharged from hospital, discharged from the army, discharge a patient.
The other main sense is to release something outward: discharge waste into a river, the battery discharges. As a noun it covers both — hospital discharge, an industrial discharge — and in medicine a discharge is fluid from a wound or the body. It also means to carry out a duty: discharge your responsibilities. Note dishonourable discharge, and that in law a discharge can also mean releasing somebody from a debt or an obligation.
1verbofficiallyTo let somebody go officially.
“The patient was discharged from hospital as soon as her fever went down.”
2verbdischargeTo release something outward.
“The plant discharges into the estuary and has done for years.”
3verbcarryTo carry out a duty.
“She discharged the role for about a decade with no fuss.”
discharge is a releasing.
Old French deschargier means to unload — des-, off, plus chargier, to load, from the same root as cargo and charge. Every sense is an unloading: of a patient, of a battery, of a duty.
Latin
discarrico — unload
Old French
deschargier — to unload
Middle English
dischargen
English, today
discharge
From Middle English dischargen, from Old French deschargier (“to unload”), from Latin discarrico (“unload”). by surface analysis, dis- + charge.
Etymology from Wiktionary, CC BY-SA